All print heads having a fluid reservoir require bubble free liquid to exit the reservoir during the printing process, otherwise they will suffer from performance issues. For example, in solid ink printers, ink solidifies when cooled and melts when heated. Heated ink is used during the printing process. When the printer is not being used, such as when the printer is turned off overnight, the ink solidifies. During solidification, the ink contracts and air is introduced into the system. The ink with the air is then re-melted when the printer becomes active again. The air present in the re-melted ink forms bubbles that cause missing jets when the printer attempts to print. In another example, water-based ink printing systems also suffer from the introduction of bubbles into the ink.
All print heads with a fluid reservoir must go through a purging process to rid the ink of the bubbles. Ink is purged out the jet stack faceplate of the print head. The purging process wastes valuable ink. Without purging the ink prior to printing after the ink is re-melted, the print quality is low and print jobs can be ruined. However, purging ink wastes good ink and increases printing costs. An alternative to the purging process in the solid ink example is to keep the ink melted, which means keeping the printer powered on, which significantly reduces the energy efficiency of the printing process. Embodiments of the invention address these and other limitations of the currently available printing systems.